This invention relates to a package for use in the microwaving of cookable items, such as popcorn, other food products, or other substances, and more specifically pertains to the controlled venting of any pressure or steam generated within their container during microwaving to assure that such is effectively released to the atmosphere, preferably without substantially opening of the structured bag, for maintaining the freshly cooked and heated texture for the food product, until the bag is physically opened for consumption or use by the consumer.
A wide variety of controls are known for the cooking of miscellaneous food products within a microwave oven, and more specifically there has been substantial design activity in the fabrication of containers as used for holding particularly popcorn kernels, or the like, during shipment, storage, merchandising, and especially during their microwaving to the edible form.
Examples of these type of prior art containers are shown in the United States patent to Katz, et al, U.S. Pat. No. 3,851,574. This patent, as can be seen, discloses a collapsable bag, structured of paper, or glassine paper, and which incorporates, in its configuration, a central opening that serves as a steam exhaust of restricted size for the purpose of allowing the pressure to be vented that has been generated during microwaving. In addition to the foregoing, the U.S. Pat. No. 4,571,337, to Cage, et al, shows a container and its popcorn ingredient for microwave usage. In this particular container, which appears to be structured very similar to that which is shown in the Katz disclosure, the desired object is to attain venting and release of steam from the container, during microwaving, and particularly through the center strip portion of the shown bag that is located as structured intermediate the formed lateral gussets of the shown container. Hence, as can be seen from these two principal prior art references, which specifically disclose bags or containers for use in a microwave setting, the concept for attaining venting is done simply through providing a separation between a pair of adjacent walls, more specifically at the upper central section of the shown container, and which requires an opening of the main top seal for the bag during microwaving, to achieve their intended results. In fact, an opening of the upper seal is principally what the design of U.S. Pat. No. 4,571,337 intends to achieve. To the contrary, the current invention very precisely controls the venting of pressure and steam from a microwavable bag, by channelling such pressure "through" particular structured wall(s), while maintaining the integrity of the main top seal of the bag even during and after the performance of a microwaving procedure.
Although numerous disclosures have been provided to cover a wide variety of film liners for containers, and the like, and particularly for use in a microwave setting, and which containers incorporate a wide variety of various said liners, in actual practice, the inner liner of film usually employed in the fabrication of such bags has been restricted to the polyester type film, which is obtainable from duPont Company. This is because no other film commercially available is able to withstand the heat of the microwave cooking, and also, other films have a tendency to break away at the top during cooking to provide venting, such as previously explained with respect to the two identified prior art patents. Additionally, although the prior art structures, as previously identified, claim to provide adequate shelf life for their packaged ingredients, in actual practice, the moisture barrier provided by the currently used film, as mentioned, is rather poor in preservation, and as a result, both the marketers and the consumers utilizing such bagged popcorn, or the like, usually overwrap each individual bag with another and separate moisture barrier film such as a polypropylene film, for product preservation and added shelf-life.
Another problem, as previously briefly alluded to, is that in current style popcorn bags available in the art, the seals formed by the films are generally of such weak quality that they tend to release and fully burst open the unsupported top of the bag during the cooking process. In practice, it has been found that the so-called venting alluded to in the previously described patents are in practice actually a function of the polyester film seal strength, and such is generally not controllable and has no flexibility in adjustment with respect to the various types of foods that may be cooked within such structured bags, and in the microwave oven. In addition, the types of foods, the volumes of foods, and the amount of their steam generation and developed internal pressure cannot be taken into consideration during the usage of the type of bags heretofore structured, since their upper seals simply break when exposed to some degree of pressure. Furthermore, with respect to these types of problems, and the lack of proper barrier against moisture permeation, which has led to the supplemental wrapping of such bags by the consumers, such have restricted the type of foods that can be packed in the self-opening style standard bags, as are used in microwaves.
Other U.S. patents disclosing various types of packages for foods include the U.S. Pat. Nos. 2,865,768, to Barnes, et al, 2,673,806, to Colman, 3,689,291, to Draper, 2,189,174, to Hohl, 2,633,284, 3,023,947, 3,052,554, 3,188,215, 3,204,760, 3,293,048, 3,478,952, 3,511,746, 3,851,574, 3,865,302, 3,973,045, 3,997,677, 4,013,798, 4,141,487, 4,145,449, 4,210,674, 4,261,504, 4,292,332, 4,358,446, 4,390,554, and 4,456,164.
It is, therefore, the principal object of the current invention to provide a microwavable bag, which has the attributes of affording both resistance against absorption of the food product or its moisture into the bag, either during storage, application, cooking, or subsequent to heating, while at the same time, providing a moisture barrier against either the entrance of moisture into the bag, which may under usual circumstances cause deleteriousness to the food stored therein, or allow moisture to escape from the food product, causing its desiccation. This invention generally provides a multi-laminar structured bag, having either a paper or polymer outer coating, a moisture barrier intermediate coating, and a non-wicking innercoating which cooperates with further film or adhesive for providing the convenient and proper seals necessary for enclosing and storing the food product therein, until it is subject, sometime later, to microwaving.
Another object of this invention is to provide a microwavable bag which retains its seals, throughout its periphery, even during and subsequent to microwaving, while at the same time, affording controlled venting of its interiorly generated steam and pressure without necessitating any further opening of the bag, other than that which is provided by means of prearranged and structured vent chamber(s) constructed into the bag during its fabrication.
Another object of this invention is to provide a fuller control over the type and style of venting that may be attained for a microwavable package, which can be readily regulated and achieved by a designed fabrication of the bag through a selection of the dimensions for the vent chamber, and its passages, to be structured into the package during its initial assembly.
These and other objects may become more apparent to those skilled in the art upon reviewing the summary of this invention, and upon undertaking a study of the description of its preferred embodiment, in view of the drawings.